Revert "Use httpdomain extension"

This reverts commit 875ef404.

docs/conf.py

@@ -25,7 +25,7 @@
 
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
-extensions = ['sphinxcontrib.httpdomain']
+extensions = []
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']